A list of GW2 Ascended armor stats and their comparison with exotics.
Ascended Armor Stats
All Ascended armor pieces contain a single defensive infusion slot per armor piece, which can be outfitted with infusions containing agony resists or infusions with +5 stats. See this guide on acquiring them (they can be crafted or brought from laurel vendors in PvE/WvW).
Defense stats on the Ascended armor pieces
Ascended Armor Stats compared to exotics
The major thing to take away from this comparison is that the stat differences are all ~5%. For items such as boots/gloves etc the stat difference is 1-2 stat more between exotic and ascended. For items such as coat/leggings the difference is slightly bigger but that is because they have more stats. It all rounds up to about 5% stat increase by upgrading from exotics to Ascended.